The dipyridylium herbicides, paraquat and diquat

Akhavein, A. A.; Linscott, D. L.

doi:10.1007/978-1-4615-8437-7_6

Cited by 31 publications

(25 citation statements)

References 91 publications

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“…Many adsorption studies in the literature were carried out with aqueous clay systems containing several grams of clay per liter. In practice, paraquat and diquat are applied as herbicides at the micromolar level (Akhavein and Linscott, 1968); however, in previous studies the equilibrium concentrations of these materials were reported at the millimolar level. The present study was carried out using the organocations shown in Figure 1 at the micromolar level and clay at the mg/ Present address: School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana 47405.…”

Section: Introductionmentioning

confidence: 94%

Interactions of Some Large Organic Cations with Bentonite in Dilute Aqueous Systems

Narine

Guy

1981

Clays and clay miner.

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Abstract--Adsorption studies indicate that paraquat, diquat, and thionine are bound on bentonite by amounts greater than the measured cation-exchange capacity (CEC) of the clay. Methylene blue, new methylene blue, and malachite green are bound by amounts equal to the CEC. The unipositive organocations form aggregates on the clay surface. Aggregation increases with ionic strength and increases the apparent adsorption capacity by 25%. The aggregates are removed by washing with distilled water. Desorption studies show that the dyes are irreversibly bound, whereas the dipositive organocations are reversibly bound. Ionic strength variation reduces adsorption by 15 and 36% in the monovalent and divalent organocation-clay systems, respectively. In the clay-divalent organocation systems adsorption is greater on Na-saturated clay than on K-saturated clay. Adsorption is unchanged over the pH range 4.5-8.5 and decreases steadily below pH 4.0. Changes in adsorption due to changes in temperature are small. The study indicates that ionic strength is the most important variable in clay-organocation interactions.

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Section: Introductionmentioning

confidence: 94%

Interactions of Some Large Organic Cations with Bentonite in Dilute Aqueous Systems

Narine

Guy

1981

Clays and clay miner.

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“…The mechanism of PQ toxicity in various species has been investigated and is attributed to its redox cycling properties. Owing to a low redox potential of −446 mV [5], PQ is easily reduced to form a relatively stable and toxic radical by a single electron from intracellular enzymes including reduced nicotinamide adenine dinucleotide phosphate (NADPH)-cytochrome P450 reductase [6], xanthine oxidase [7,8], mitochondrial electron transfer enzymes [9], and nitric oxide synthases (NOS) [10,11]. The single electron reduction activity of PQ in subcellular fractions of various tissues in vitro has been compared using microsomal fractions [12].…”

Section: Introductionmentioning

confidence: 99%

Nitric oxide in paraquat‐mediated toxicity: A review

Morán

Ortíz-Ortíz

Ruiz-Mesa

et al. 2010

J Biochem & Molecular Tox

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Paraquat, a cationic herbicide, produces degenerative lesions in the lung and in the nervous system after systemic administration to man and animals. Many cases of acute poisoning and death have been reported over the past few decades. Although a definitive mechanism of toxicity of paraquat has not been delineated, a cyclic single electron reduction/oxidation is a critical mechanistic event. The redox cycling of paraquat has two potentially important consequences relevant to the development of toxicity: the generation of the superoxide anion, which can lead to the formation of more toxic reactive oxygen species which are highly reactive to cellular macromolecules; and the oxidation of reducing equivalents (e.g., NADPH, reduced glutathione), which results in the disruption of important NADPH-requiring biochemical processes necessary for normal cell function. Nitric oxide is an important signaling molecule that reacts with superoxide derived from the paraquat redox cycle, to form the potent oxidant peroxynitrite, which causes serious cell damage. Although nitric oxide has been involved in the mechanism of paraquat-mediated toxicity, the role of nitric oxide has been controversial as both protective and harmful effects have been described. The present review summarizes recent findings in the field and describes new knowledge on the role of nitric oxide in the paraquat-mediated toxicity.

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“…The bipyridylium herbicides have been investigated by many workers and a number of excellent reviews are available (CALDERBANK 1968, AlrnAVEIN andLINSCOTT 1968). Therefore, it is proposed that this section be confined primarily to a very brief review of the bipyridylium compounds properties which have relevance in the study of herbicide-humic substances interaction.…”

Section: Ill Bipyridylium Herbicidesmentioning

confidence: 98%

Humic substances reactions involving bipyridylium herbicides in soil and aquatic environments

Khan

1974

Residue Reviews

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The dipyridylium herbicides, paraquat and diquat

Cited by 31 publications

References 91 publications

Interactions of Some Large Organic Cations with Bentonite in Dilute Aqueous Systems

Interactions of Some Large Organic Cations with Bentonite in Dilute Aqueous Systems

Nitric oxide in paraquat‐mediated toxicity: A review

Humic substances reactions involving bipyridylium herbicides in soil and aquatic environments

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